Characterizing Total Atmospheric Nitrogen Deposition in National Parks in the Western United States

EPA Grant Number: F13B10174
Title: Characterizing Total Atmospheric Nitrogen Deposition in National Parks in the Western United States
Investigators: Evanoski-Cole, Ashley Ruth
Institution: Colorado State University
EPA Project Officer: Packard, Benjamin H
Project Period: August 25, 2014 through August 25, 2016
Project Amount: $84,000
RFA: STAR Graduate Fellowships (2013) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Fellowship - Atmospheric Chemistry


Atmospheric nitrogen deposition contributes to excess nitrogen loadings in the environment, which can lead to water and soil acidification, toxic conditions for aquatic plant and animal life and other detrimental effects. However, not all compounds that contribute to nitrogen deposition are currently routinely monitored, including ammonia and organic nitrogen, so the total nitrogen deposition is often underestimated. This research will investigate nitrogen deposition, including measurements of ammonia and organic nitrogen, to gain a comprehensive understanding of total nitrogen deposition.


For this study, total nitrogen deposition will be measured in national parks, such as Rocky Mountain National Park and Grand Teton National Park. In intensive field campaigns, both dry and wet deposition will be determined. The analysis of precipitation samples and real-time measurements of nitrogen species in gases and particles will provide detailed information on total deposition. Measurements will include all routinely measured components of nitrogen, as well as ammonia and organic nitrogen. In addition, meteorological information will enable analysis of emissions, source transport and deposition processes of the nitrogen components.

Expected Results:

Previous studies have estimated that organic nitrogen contributes an average of 30 percent of the total atmospheric nitrogen deposition. Ammonia also can contribute a significant amount to the total nitrogen deposition, depending on meteorological conditions, so the hourly measurements of ammonia in this study will provide more detailed information than what is routinely measured. The comprehensive quantification and characterization of total atmospheric nitrogen obtained in this research will provide a more detailed description of all important components of nitrogen deposition and how they affect different locations.

Potential to Further Environmental/Human Health Protection

A better understanding of the sources of atmospheric nitrogen deposition will lead to better calculations of the total nitrogen loading to a specific environment, which is important to understanding the environmental impact of nitrogen deposition in sensitive ecosystems. Additionally, identifying the main contributors to nitrogen deposition—as well as their trends and sources—will provide the information needed for policymakers to form air pollution controls to reduce nitrogen deposition in areas that are significantly affected by increasing nitrogen.

Supplemental Keywords:

ammonia, nitrogen cycling and deposition, organic nitroge

Progress and Final Reports:

  • 2015
  • Final